Esters of perfluoroalkyl terminated alkylene thioalkanoic acids

ABSTRACT

Sulfur-containing, perfluoroalkyl amines and their quaternary salt and amine oxide derivatives having outstanding surfactant properties are provided having the structures   WHERE Rf is straight or branched-chain perfluoroalkyl, R is hydrogen or methyl, R1 and R2 are independently hydrogen or lower alkyl, n is an integer of 1 to 3, m is an integer of 2 to 4; X is an anion, y is an integer equal to k, the valence of X; z is 0 or 1, and when z is 1, then R3 is hydrogen, lower alkyl or CH2COOH; and when z is 0, then R3 is oxygen, CH2COO , CH2CH2COO or CH2CH2CH2SO3 .

"Unite tates atent Hagen" et al.

[ Sept. 18, 1973 1 ESTERS 0F PERFLUOROALKYL TERMINATED ALKYLENE THIIOALKANOIC ACIDS [75] Inventors: Robert Bonner Hagar, Collegeville;

Gerald Joseph Walter, King of Prussia, both of Pa.

['73] Assignee: Pennwalt Corporation, Philadelphia,

22 Filed: May 20,1971

21 Appl.No.: 145,556

[52] US. 1 260/481 R, 106/271, 252/356,

12/1945 De Groote 260/490 OTHER PUBLICATIONS Schwartz et al., Surface Active Agents and Detergents," Vol. 11, lnterscience PubL, lnc., N.Y., (1958), pages 108, ll21l9.

Primary Examiner-Lorraine A. Weinberger Assistant Examiner-John F. Terapane Attorney-Stanley Litz [57] ABSTRACT Sulfur-containing, perfluoroalkyl amines and their quaternary salt and amine oxide derivatives having outstanding surfactant properties are provided having the structures where R, is straight or branched-chain perfluoroalkyl, R is hydrogen or methyl, R and R are independently hydrogen or lower alkyl, n is an integer of l to 3, m is an integer of 2 to 4; X is an anion, y is an integer equal to k, the valence of X; z is 0 or 1, and when 2 is 1, then R is hydrogen, lower alkyl or CH COOH; and when 1 is 0, then R is oxygen, CH COO, CH CH COO or cn cmcn so a 7 Claims, No Drawings ESTERS F PERFLUOROALKYL TERMINATED ALKYLENE THIOALKANOIC ACIDS This invention pertains to sulfur-containing, perfluoroalkyl amines and their quaternary salt and amine oxide derivatives. More particularly, this invention concerns a compound selected from the group consisting of and mmHmsomdHo0o(CH,)mNR R R y (the 11 compound being a readily prepared derivative of the precursor 1 compound) where R, is a straight or branched-chain perfluoroalkyl group having from to 13 carbon atoms; R is hydrogen or CH R and R are independently hydrogen or alkyl having from 1 to 4 carbon atoms; n is an integer of 1 to 3; m is an integer of 2 to 4; X is an anion selected from the group consisting of Br, Cl, l, acetate, phosphate, and sulfate; y is an integer equal to k, the valence of X; and z is 0 or 1,-provided that when 1 is 1, then R is hydrogen, alkyl of l to 4 carbon atoms or CH COOH; and when z is 0, then R is CH COO; cH,cH,coo-, CH,CH CH SO or oxygen.

The precursor compound 1 is prepared by reacting the fluorinated mercaptan R,(CH ),,Sl-l with an alltylaminoacrylate of the structure the substituents being defined above. The aminoalkyl acrylates are known compounds which are commercially available or readily prepared by standard organic synthesis techniques. The mercaptans, R,{Cl-l ),,SH, are known and are described, for example, in the patents to N. O. Brace, U.S. 3,172,910, Mar. l9, 1965 and to Hauptschein et al., U.S. Pat. No. 3,544,663, Dec. 1, 1970. Approximately stoichiometric amounts of the mercaptan and the aminoalkyl acrylate are re acted at from about to 150 C., neat, or in a suitable solvent such as n-butanol, ethanol, 2-propanol, diethylene-glycol-monoethyl ether, or Z-ethoxy ethanol, to prepare the amine adduct 1 in high yield, e.g., about 75 to 100 percent, from which the solvent, and

any unrcacted starting material is removed by a simple stripping operation.

The thus prepared amine adduct 1 is converted to the derivative compound 11 by techniques well known to the organic chemist. For instance, an amphoteric surfactant is prepared by reacting substantially stoichiometric amounts of the amine with such reactants as chloroacetic acid, sodium chloroacetate, potassium chloroacetate, propane sultone, propiolactone, and the like at temperatures within the range of about 10 to 150 C. Cationic surfactants are prepared in the conventional manner by reacting the amine compound 1, neat, or in suitable solvent, such as n-butanol, ethanol or 2-propanol, at about 10 to 150 C., with typical quaternizing reactants exemplified by methyl iodide, ethyl iodide, and the like. The amine precursor of this invention is converted to its amine oxide derivative by treating the amine with aqueous hydrogen peroxide at about 0 to 50 C.

The following examples are presented to illustrate the preparation of the novel compounds of this invention and to demonstrate their valuable properties.

Example 1 Reaction of C F, C H SH with Dimethylaminoethyl Methacrylate A flask fitted with a stirrer and reflux condenser is charged with 103 grams of isopropyl alcohol, 64.5 grams (0.15 mole) of (CF CF(CF ).,CH CH SH and 23.6 grams (0.15 mole) of dimethylaminoethyl methacrylate. Three drops of 10 percent NaOH is added and the mixture heated to reflux for 3 hours. The solvent is stripped off to yield the clear liquid product (CF CF(CF ).,C H SCl-l CH(CH )COOC H N(CH )z' The structure is confirmed by infrared spectoscopy.

Example 2 Reaction of Other Mercaptans with Aminoalkyl Acrylates The procedure of Example 1 is followed in reacting various representative fluoroalkyl mercaptans of the structures:

with representative aminoalkyl acrylates of the structures to produce the 1:1 amine adducts of this invention, i.e., the amine 1 of the formula Example 3 Preparation of Amphoteric Surfactants Fifty grams (0.085 mole) of the amine prepared in Example 1 and 7.9 grams (0.084 mole) of chloroacetic acid are charged to an open resin flask fitted with a stirrer. The mixture is gradually heated to C., then held at this temperature for 20 minutes. On cooling, the tough, taffy-like amphoteric surfactant [(CF CF(CF CH CH SCH CH(CH )COOCH CH N(CH CH COOH] CI' is recovered. In like manner, the amines produced in Example 2 are converted to the corresponding amphoteric compound derivatives. The chloride ion may be removed by treating the product with alcoholic base, for example NaOH in ethanol, KOH in isopropyl alcohol, or with a salt such as potassium acetate, which causes precipitation of the chloride as a salt.

Example 4 Preparation of Cationic Surfactants 4 are set forth in the following Table I. Also shown is the surface tension data for the compound C F,,SO NH(C- H -,N (CH CH CH COO, the only fluorinecontaining amphoteric surfactant presently commer cially available. It can be seen that the amphoterics of this invention, particularly the shorter chain compound, give lower surface tensions at lower concentrations, an important advantage with these very expensive materials.

TABLE 1 Surface tension, dyncs/em. at C. at concentration of (CF CF(CF ),C H SCH CH(CH )COOC,H N (CH- In like manner, the amines produced in Example 2 are converted to the corresponding cationic (quaternary salt) surfactants.

Example 5 Preparation of Propane Sulfonic Acid Betaine Derivative The amine adduct of Example 1 is dissolved in an equal weight of ethanol and an equimolar quantity of propane sultone is added. The mixture is allowed to stand at room temperature for 24 hours, and then evaporated to constant weight on a steam bath to yield the betaine product,

Example 6 Preparation of Amine Oxides added and stirring continued for six hours. The excess peroxide is decomposed with 5 percent Pd-on-charcoal and the mixture filtered to give a solution of the product Example 7 Surface tension measurements of dilute aqueous solutions of representative compounds of the invention The compounds embodied in this invention are surface active agents giving a high degree of surface tension reduction at concentrations as low as 0.1 percent by weight and less. These new fluoroalkyl surfactants are of special value in the formulation of phosphorichydrochloric acid type cleaning solutions used on concrete and metals. In acidic baths for metal descaling, pickling, and etching, these compounds serve as both wetting agent and corrosion inhibitor. The new surfactants are also useful as corrosion inhibitors and leveling agents for aqueous wax and/or resin emulsions that are widely used in the form of the so-called self-polishing wax formulations which dry to a shine without buffing. Modern heavy-duty floor waxes are often formulated with resins that are insoluble in alkaline cleaning compositions, e.g., soaps and detergents, even though the resins are easily solubilized by acidic cleaners. The cationic, alkaline-insoluble, fluoroalkyl surfactants of this invention are ideally suited for such formulations, improving the leveling, gloss, and wetting power while minimizing streaking. For instance, a standard selfpolishing floor wax formulation is as follows:

' Parts by Component weight Aqueous dispersion containing 30% by weight of polyethylene resin particles having melting point 2 l 322lF. 222 Aqueous dispersion containing 15% by weight I of acrylic resin ("Rhoplex 3-83") l Diethylene giycol monoeth l ether.

CH,0HC ,OCH,CH,O ,H, 60 Nonyl phenol-ethylene oxide condensation product, 9-l0 mols ethylene oxide/mol of phenol l2 Tn(2-ethylhexyl)phosphate 14 Distilled water I968 Such a formulation does not dry to a satisfactory gloss on floor tiles, but the incorporation of 0.3 percent or less of a surfactant compound embodied herein does provide a uniform, glossy film therefrom.

A preferred embodiment of the invention is the compound having amphoteric surfactant properties, particularly the compounds,

We claim: 1. A compound selected from the group consisting of where R, is a straight or branched perfluoroalkyl group having from to 13 carbon atoms; R is hydrogen or CH;,; R and R are independently hydrogen or alkyl having from 1 to 4 carbon atoms; n is an integer of l to 3; m is an integer of 2 to 4; X is an anion selected from the group consisting of Br, Cl, 1, acetate, phosphate, and sulfate; y is an integer equal to k, the valence of X; and z is O or 1, provided that when 2 is l, then R is hydrogen, alkyl of l to 4 carbon atoms or CH' COO- H; and when 2: is 0, then R 'is CH COO; CH CH COO"; CH CH CH SO or oxygen.

2. A compound according to claim 1 wherein n is 2.

3. A compound according to claim 1 wherein R' and R are each methyl, m is 2, and R is CH 4. A compound according to claim 3 where n is 2.

5. The compound having the formula where R, is a straight or branched perfluoroalkyl group having from 5 to 13 carbon atoms.

6. A compound according to claim 5 where R! is s)2 2)4 7. A compound according to claim 5 where 

2. A compound according to claim 1 wherein n is
 2. 3. A compound according to claim 1 wherein R1 and R2 are each methyl, m is 2, and R is CH3.
 4. A compound according to claim 3 where n is
 2. 5. The compound having the formula (Rf(CH2)2SCH2CH(CH3)COO(CH2)2N(CH3)2CH2COOH) Cl where Rf is a straight or branched perfluoroalkyl group having from 5 to 13 carbon atoms.
 6. A compound according to claim 5 where Rf is (CF3)2CF(CF2)4
 7. A compound according to claim 5 where Rf is (CF3)2CF(CF2)6 